diff mbox

spi: cadence: Add usleep_range() for cdns_spi_fill_tx_fifo()

Message ID 1523880451-37748-1-git-send-email-sxauwsk@163.com (mailing list archive)
State New, archived
Headers show

Commit Message

sxauwsk@163.com April 16, 2018, 12:07 p.m. UTC
In case of xspi work in busy condition, may send bytes failed then caused
communication failure. once something wrong, spi controller did't work any more.

My test found this situation appear in both of read/write operation.
so when TX FIFO is full, add one byte delay before send data.

Signed-off-by: sxauwsk <sxauwsk@163.com>
---
 drivers/spi/spi-cadence.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--
1.7.9.5


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diff mbox

Patch

diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index 5c9516a..9694042 100644
--- a/drivers/spi/spi-cadence.c
+++ b/drivers/spi/spi-cadence.c
@@ -313,6 +313,14 @@  static void cdns_spi_fill_tx_fifo(struct cdns_spi *xspi)

	while ((trans_cnt < CDNS_SPI_FIFO_DEPTH) &&
 	       (xspi->tx_bytes > 0)) {
+
+		/* When xspi in busy condition, bytes may send failed,
+		 * then spi control did't work thoroughly, add one byte delay
+		 */
+		if (cdns_spi_read(xspi, CDNS_SPI_ISR_OFFSET) &
+		    CDNS_SPI_IXR_TXFULL_MASK)
+			usleep_range(10, 20);
+
 		if (xspi->txbuf)
 			cdns_spi_write(xspi, CDNS_SPI_TXD, *xspi->txbuf++);
 		else